The information throughput of information-oriented society has been increasing rapidly. In particular, storage devices store increasing amounts of information at higher areal densities in devices of ever decreasing form factors. Thus, technology that provides increased storage capacity such as high-density magnetic recording has received increasing attention to satisfy the demand for increased storage capacity. To achieve high-density magnetic recording, more minute magnetic-recording bits are desired. To this end, the bit size of a unit of magnetically recorded information has continued to decrease in size with an attending rise in the density of information stored in high-density, magnetic-recording storage devices, such as hard-disk drives (HDDs).
However, the small bit sizes attending the development of high-density magnetic recording are impacted by reduced thermal stability of the magnetization of the small magnetic-recording bits in which information is stored so that magnetically recorded information fades away with time because of thermal decay, which adversely affects non-volatility of magnetically recorded information. Accordingly, to ensure the thermal stability of the magnetically recorded information, the coercivity of magnetic-recording media has increased. However, as is known in the art, the higher the coercivity is, the more difficult magnetic recording becomes. To perform magnetic recording on a high-coercivity magnetic-recording medium, a magnetic-recording field from a write element of a magnetic-recording head is provided that is greater than the coercivity of the magnetic-recording medium, and possesses a high magnetic-recording-field gradient. Although magnetic-recording head structures have been refined and new materials have been developed, magnetic recording within the small bit sizes attending high-density magnetic recording is becoming increasingly more challenging.
Thus, alternative magnetic-recording techniques have been proposed such as heat-assisted magnetic recording (HAMR), which applies heat to an area to be recorded utilizing a phenomenon that the magnetic-recording-medium coercivity reduces with the application of heat, which allows a magnetic-recording medium with high coercivity at room temperature to be written with a lower magnetic-recording field at a higher temperature. HAMR, however, only heats the magnetic-recording medium to reduce the coercivity; and, the magnetic-recording field from the write element of the magnetic-recording head still has to provide the high magnetic-recording-field gradient, which is the source of abrupt transitions between recorded bits attending high-density magnetic recording. In writing the magnetic-recording medium, the write element of the magnetic-recording head is brought close to the magnetic-recording medium in order to write the abrupt transitions. However, since a heat source utilized to heat the magnetic-recording medium is provided in the vicinity of the air-bearing surface (ABS) near the write element of the magnetic-recording head, the fly height can not be reduced because of the protrusion of the magnetic-recording head due to heating. Thus, engineers and scientists engaged in the development of high-density magnetic-recording are interested in finding new means for recording information at high areal densities.